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蔬菜是人们生活中不可缺少的副食品,它的营养功能主要是供给人体所必需的多种维生素、无机盐、微量元素、酶及芳香物质等;此外,还可补充人体中一部分热能和蛋白质的需要,还有维持体内酸碱平衡和帮助消化,增强体质等功能。中学生物教师结合植物学教学,对日常生活中常吃的蔬菜植物的分类、鉴别和可食用的部分,应进行准确地讲解,然而,目前这方面存在着模糊和错误的概念。下面就蔬菜植物中有关的十个问题,加以具体地说明。 相似文献
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本研究采用EBV-EA诱导抑制实验的方法,对40种蔬菜,60个品种,共150个样品的防癌抗促作用效果进行了筛选与比较,其中具有中等以上抑制活性的样品117个,占样品总数的78%,尤其以非洲野苋菜、辣椒、羽衣甘蓝、山药芋头、苦瓜及紫苏、罗勒等一些芳香莱的效果较好。不同品种、不同植株部位、不同提取方法以及不同产地,对蔬菜的抗促活性也有影响,值得进一步研究。 相似文献
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代谢工程在芳香化合物生物合成研究中的应用 总被引:4,自引:0,他引:4
生物技术和代谢工程的发展促进了生物合成研究。概述了近年来利用微生物莽草酸途径进行芳香化合物生物合成研究的现况、代谢工程在提高天然芳香化合物产量和扩大合成非天然产生的芳香化合物范围的应用的进展 ,特别是整体代谢工程对提高第二代工程菌产量的作用。指出了生物合成法是生产氨基酸及其它生物小分子如奎尼酸、维生素和抗生素等的未来趋势 ,在工业化生产中有着广阔的应用前景。 相似文献
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几种野生蔬菜硝酸盐及维生素C含量的研究 总被引:11,自引:1,他引:11
野生蔬菜不仅具有较高的营养价值,还有相当高的医疗价值。近代研究表明,过量的食入硝酸盐,会诱发消化系统癌变,而维生素 C 有防癌作用,因此硝酸盐和维生素 C含量为评价蔬菜品质的重要指标之一。一般栽培的叶菜类蔬菜如白菜、菠菜、苔菜等硝酸盐含量很高,平均存4000mg/kg 鲜重左右。野生蔬菜中的硝酸盐及维生素 C 含量如何呢?我们仅对几种分布广泛,食用历史较长,营养价值较高的野生蔬菜进行了研究,以期为科学地有选择性地开发野生蔬菜资源提供有价值的依据。 相似文献
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祁门红茶、龙井茶、茉莉花茶、白兰花茶和乌龙茶,不仅是中国的名优茶,而且也是主要出口茶类。这些名茶芳香馥郁,品质独特,与其含有大量芳香物质密切相关。本文综合有关研究成果,简要概述了这五类名优茶中主要芳香物质构成、特点及变化。 相似文献
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设施巨峰葡萄二次果果实品质及芳香化合物组分分析 总被引:2,自引:0,他引:2
为了明确设施栽培下巨峰葡萄二次果果实品质及芳香化合物组分,采用固相微萃取技术及气相-质谱联用技术测定芳香化合物含量,研究其果实品质及芳香物质相对含量与露地巨峰葡萄的差异。结果显示:(1)巨峰葡萄二次果较露地巨峰葡萄果实的单粒重、纵径、横径分别减少了8.23%、11.74%、10.63%,果实总糖含量提高了8.59%,可滴定酸含量有所提高但差异不显著,果肉Vc含量(1.47mg·kg-1)显著低于露地果实(2.00mg·kg-1),果皮原花青素含量(24.40mg·g-1)是露地果实的3.37倍,果实色泽较露地果实显著加深。(2)巨峰二次果中醛类化合物的相对含量最高,为53.55%;露地巨峰中酯类化合物的相对含量最高,为61.36%;乙酸乙酯在露地巨峰(51.00%)和二次果(33.65%)中的相对含量均较高,说明二者均具有明显的草莓香味;但巨峰二次果中相对含量最高的芳香化合物是2-己烯醛(41.14%),且显著高于露地果实中的相对含量(16.31%)。研究表明,巨峰二次果的总糖含量显著高于露地栽培巨峰,但二次果的果粒小;由于葡萄果实中的2-己烯醛对其芳香化合物的组分构成了非常重要的影响,改变了葡萄的果实风味,因此设施栽培下巨峰葡萄二次果果实在风味上与露地栽培果实存在一定差异。 相似文献
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In experiments on Black Sea skates (Raja clavata), the potential of the receptor epithelium of the ampullae of Lorenzini and spike activity of single nerve fibers connected to them were investigated during electrical and temperature stimulation. Usually the potential within the canal was between 0 and –2 mV, and the input resistance of the ampulla 250–400 k. Heating of the region of the receptor epithelium was accompanied by a negative wave of potential, an increase in input resistance, and inhibition of spike activity. With worsening of the animal's condition the transepithelial potential became positive (up to +10 mV) but the input resistance of the ampulla during stimulation with a positive current was nonlinear in some cases: a regenerative spike of positive polarity appeared in the channel. During heating, the spike response was sometimes reversed in sign. It is suggested that fluctuations of the transepithelial potential and spike responses to temperature stimulation reflect changes in the potential difference on the basal membrane of the receptor cells, which is described by a relationship of the Nernst's or Goldman's equation type.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. I. M. Sechenov, Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Pacific Institute of Oceanology, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Neirofiziologiya, Vol. 12, No. 1, pp. 67–74, January–February, 1980. 相似文献
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N. P. Vesselkin Yu. V. Natochin 《Journal of Evolutionary Biochemistry and Physiology》2010,46(6):592-603
Evolution of living organisms is closely connected with evolution of structure of the system of regulations and its mechanisms.
The functional ground of regulations is chemical signalization. As early as in unicellular organisms there is a set of signal
mechanisms providing their life activity and orientation in space and time. Subsequent evolution of ways of chemical signalization
followed the way of development of delivery pathways of chemical signal and development of mechanisms of its regulation. The
mechanism of chemical regulation of the signal interaction is discussed by the example of the specialized system of transduction
of signal from neuron to neuron, of effect of hormone on the epithelial cell and modulation of this effect. These mechanisms
are considered as the most important ways of the fine and precise adaptation of chemical signalization underlying functioning
of physiological systems and organs of the living organism 相似文献